Dosages, requirements, and deficiency prevalence

"In the United States and Europe, >40% of the adult population >50 years of age is vitamin D deficient . More than a dozen different studies of serum 25- (OH)D concentrations in 55,000 adults and children from many countries within the European Union reported that 13% of individuals had 25-(OH)D concentrations of <30 nmol/L and 40% had concentrations of <50 nmol/L (Cashman et al., 2016). In Australia, 4% of the population had a 25-(OH)D level <25 nmol/L, 31% (22% men; 39% women) had a level of <50 nmol/L, and 73% had a level of <75 nmol/L (Daly et al., 2012). "

"The optimal 25(OH)D concentration for maximizing the health beneﬁts of vitamin D is a hotly debated topic, but there is general consensus that concentrations >50 nmol/L are desirable in the general population (based primarily on bone health outcomes). "